The objective of our research is to investigate glucose and lactate metabolism in hospitalized patients with malignant solid tumors. Using isotope tracer procedures, the production, utilization and oxidation of glucose and lactate will be measured. The possible relationship between lactate production and tumor growth will be investigated by observations on the effect of cancer therapy on lactate metabolism. In addition, host metabolic response to nutritional supplementation by short term intravenous hyperalimentation will be evaluated.